Peroxiredoxins (Prxs) are cysteine dependent antioxidants that play a vital role in regulating the levels of peroxides, peroxynitrite and organic hydroperoxides. Peroxiredoxin 3 (Prx3) belongs to the typical 2-Cys Prx family and thioredoxin like super family with thioredoxin fold. The present study describes the identification , characterization and functional analysis of prx3 (HaPrx3) from big belly seahorse (Hippocampus abdominalis) . The cDNA with the 726 bp open reading frame encoded 241 amino acid protein with 26.20 kDa molecular weight. HaPrx3 shared the highest similarity and identity with the protein sequence of Oplegnathus fasciatus (Striped beakfish) and according to the phylogenetic analysis HaPrx3 clustered within the branch of teleost.
The highest HaPrx3 mRNA elevation was observed for the ovaries following blood, brain and testis among fourteen tissues of seahorse. The HaPrx3 transcripts in blood and liver tissues were showed significant upregulation for the immune challenge with lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (poly I:C) , Edwardsiella tarda and Streptococcus iniae displaying their immune defense against pathogenic infection. Furthermore, recombinant HaPrx3 (rHaPrx3 ) was showed dose dependent DNA protection ability against the reactive oxygen species generated from the metal catalyzed oxidation system. The rHaPrx3 was able to reduce the nuclear fragmentation and apoptotic body formation in the H2O2 treated cells. In summary, these findings justify the redox potential during the oxidative stress conditions and innate immune responses of HaPrx3 in Hippocampus abdominalis.